This application claims priority from copending provisional application Serial No. 60/385,695, filed Jun. 4, 2002, the entire disclosure of which is hereby incorporated by reference.
Serotonin (5-Hydroxytryptamine)(5-HT) receptors play a critical role in many physiological and behavioral functions in humans and animals. These functions are mediated through various 5-HT receptors distributed throughout the body. There are now approximately fifteen different human 5-HT receptor subtypes that have been cloned, many with well-defined roles in humans. One of the most recently identified 5-HT receptor subtypes is the 5-HT6 receptor, first cloned from rat tissue in 1993 (Monsma, F. J.; Shen, Y.; Ward, R. P.; Hamblin, M. W. Molecular Pharmacology 1993, 43, 320-327) and subsequently in human tissue (Kohen, R.; Metcalf, M. A.; Khan, N.; Druck, T.; Huebner, K.; Sibley, D. R. Journal of Neurochemistry 1996, 66, 47-56). The receptor is a G-protein coupled receptor (GPCR) positively coupled to adenylate cyclase (Ruat, M.; Traiffort, E.; Arrang, J-M.; Tardivel-Lacombe, L.; Diaz, L.; Leurs, R.; Schwartz, J-C. Biochemical Biophysical Research Communications 1993, 193, 268-276). The receptor is found almost exclusively in the central nervous system (CNS) areas both in rat and in human. In situ hybridization studies of the 5-HT6 receptor in rat brain using mRNA indicate principal localization in the areas of 5-HT projection including striatum, nucleus accumbens, olfactory tubercle, and hippocampal formation (Ward, R. P.; Hamblin, M. W.; Lachowicz, J. E.; Hoffman, B. J.; Sibley, D. R.; Dorsa, D. M. Neuroscience 1995, 64,1105-1111).
There are many potential therapeutic uses for 5-HT6 ligands in humans based on direct effects and on indications from available scientific studies. These studies include the localization of the receptor, the affinity of ligands with known in vivo activity, and various animal studies conducted so far.
One potential therapeutic use of modulators of 5-HT6 receptor function is in the enhancement of cognition and memory in human diseases such as Alzheimer""s. The high levels of receptor found in important structures in the forebrain, including the caudate/putamen, hippocampus, nucleus accumbens, and cortex suggest a role for the receptor in memory and cognition since these areas are known to play a vital role in memory (Gerard, C.; Martres, M.-P.; Lefevre, K.; Miquel, M. C.; Verge, D.; Lanfumey, R.; Doucet, E.; Hamon, M.; E I Mestikawy, S. Brain Research, 1997, 746, 207-219). The ability of known 5-HT6 receptor ligands to enhance cholinergic transmission also supported the potential cognition use (Bentley, J. C.; Boursson, A.; Boess, F. G.; Kone, F. C.; Marsden, C. A.; Petit, N.; Sleight, A. J. British Jornal of Pharmacology, 1999, 126(7), 1537-1542). Studies have found that a known 5-HT6 selective antagonist significantly increased glutamate and aspartate levels in the frontal cortex without elevating levels of noradrenaline, dopamine, or 5-HT. This selective elevation of neurochemicals known to be involved in memory and cognition strongly suggests a role for 5-HT6 ligands in cognition (Dawson, L. A.; Nguyen, H. Q.; Li, P. British Journal of Pharmacology, 2000, 130(1), 23-26). Animal studies of memory and learning with a known selective 5-HT6 antagonist found some positive effects (Rogers, D. C.; Hatcher, P. D.; Hagan, J. J. Society of Neuroscience, Abstracts 2000, 26, 680).
A related potential therapeutic use for 5-HT6 ligands is the treatment of attention deficit disorders (ADD, also known as Attention Deficit Hyperactivity Disorder or ADHD) in both children and adults. Because 5-HT6 antagonists appear to enhance the activity of the nigrostriatal dopamine pathway and because ADHD has been linked to abnormalities in the caudate (Ernst, M; Zametkin, A. J.; Matochik, J. H.; Jons, P. A.; Cohen, R. M. Journal of Neuroscience 1998, 18(15), 5901-5907), 5-HT6 antagonists may attenuate attention deficit disorders.
Early studies examining the affinity of various CNS ligands with known therapeutic utility or a strong structural resemblance to known drugs suggests a role for 5-HT6 ligands in the treatment of schizophrenia and depression. For example, clozapine (an effective clinical antipsychotic) has high affinity for the 5-HT6 receptor subtype. Also, several clinical antidepressants have high affinity for the receptor as well and act as antagonis at this site (Branchek, T. A.; Blackburn, T. P. Annual Reviews in Pharmacology and Toxicology 2000, 40, 319-334).
Further, recent in vivo studies in rats indicate 5-HT6 modulators may be useful in the treatment of movement disorders including epilepsy (Stean, T.; Routledge, C.; Upton, N. British Journal of Pharmacology 1999, 127 Proc. Supplement 131P and Routledge, C.; Bromidge, S. M.; Moss, S. F.; Price, G. W.; Hirst, W.; Newman, H.; Riley, G.; Gager, T.; Stean, T.; Upton, N.; Clarke, S. E.; Brown, A. M. British Journal of Pharmacology 2000, 130(7), 1606-1612).
Taken together, the above studies strongly suggest that compounds which are 5-HT6 receptor ligands may be useful for therapeutic indications including: the treatment of diseases associated with a deficit in memory, cognition, and learning such as Alzheimer""s and attention deficit disorder; the treatment of personality disorders such as schizophrenia; the treatment of behavioral disorders, e.g., anxiety, depression and obsessive compulsive disorders; the treatment of motion or motor disorders such as Parkinson""s disease and epilepsy; the treatment of diseases associated with neurodegeneration such as stroke and head trauma; or withdrawal from drug addiction including addiction to nicotine, alcohol, and other substances of abuse.
Therefore, it is an object of this invention to provide compounds which are useful as therapeutic agents in the treatment of a variety of central nervous system disorders related to or affected by the 5-HT6 receptor.
It is another object of this invention to provide therapeutic methods and pharmaceutical compositions useful for the treatment of central nervous system disorders related to or affected by the 5-HT6 receptor.
It is a feature of this invention that the compounds provided may also be used to further study and elucidate the 5-HT6 receptor.
These and other objects and features of the invention will become more apparent by the detailed description set forth hereinbelow.
The present invention provides a 1-(aminoalkyl)-3-sulfonylindole or -indazole of formula I 
wherein
W is N or CR2;
R is H, halogen, CN, OCO2R7, CO2R8, CONR9R10, SOpR11, NR12R13, OR14, COR15 or a C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, C3-C7cycloalkyl, cycloheteroalkyl, aryl or heteroaryl group each optionally substituted;
R1 is an optionally substituted C1-C6alkyl, C3-C7cycloalkyl, aryl, or heteroaryl group or an optionally substituted 8- to 13-membered bicyclic or tricyclic ring system having a N atom at the bridgehead and optionally containing 1, 2 or 3 additional heteroatoms selected from N, O or S;
R2 is H, halogen, or a C1-C6alkyl, C1-C6alkoxy, C3-C7cycloalkyl, aryl or heteroaryl group each optionally substituted;
R3 and R4 are each independently H or an optionally substituted C1-C6alkyl group;
R5 and R6 are each independently H or a C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, C3-C7cycloalkyl, cycloheteroalkyl, aryl or heteroaryl group each optionally substituted or R5 and R6 may be taken together with the atom to which they are attached to form an optionally substituted 5- to 8-membered ring optionally containing an additional heteroatom selected from O, NR16 or SOx;
m is 0 or an integer of 1, 2 or 3;
n is an integer of 2, 3, 4 or 5;
p and x are each independently 0 or an integer of 1 or 2;
R7, R8, R11, R15 and R16 are each independently H or a C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, C3-C6cycloalkyl, cycloheteroalkyl, aryl or heteroaryl group each optionally substituted;
R9 and R10 are each independently H or a C1-C6alkyl or C3-C7cycloalkyl group each optionally substituted or R9 and R10 may be taken together with the atom to which they are attached to form a 5- to 7-membered ring optionally containing another heteroatom selected from O, NR18 or S;
R12 and R13 are each independently H or an optionally substituted C1-C4alkyl group or R12 and R13 may be taken together with the atom to which they are attached to form a 5- to 7-membered ring optionally containing another heteroatom selected from O, NR17 or SOq;
R14 is a C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, C3-C7cycloalkyl, cycloheteroalkyl, aryl or heteroaryl group each optionally substituted;
q is 0 or an integer of 1 or 2; and
R17 and R18 are each independently H or a C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, C3-C7cycloalkyl, cycloheteroalkyl, aryl or heteroaryl group each optionally substituted; or
a stereoisomer thereof or a pharmaceutically acceptable salt thereof.
The present invention also provides methods and compositions useful for the therapeutic treatment of central nervous system disorders related to or affected by the 5-HT6 receptor.
The 5-hydroxytryptamine-6 (5-HT6) receptor is one of the most recent receptors to be identified by molecular cloning. Its ability to bind a wide range of therapeutic compounds used in psychiatry, coupled with its intriguing distribution in the brain has stimulated significant interest in new compounds which are capable of interacting with or affecting said receptor. Significant efforts are being made to understand the possible role of the 5-HT6 receptor in psychiatry, cognitive dysfunction, motor function and control, memory, mood and the like. To that end, compounds which demonstrate a binding affinity for the 5-HT6 receptor are earnestly sought both as an aid in the study of the 5-HT6 receptor and as potential therapeutic agents in the treatment of central nervous system disorders, for example see C. Reavill and D. C. Rogers, Current Opinion in Investigational Drugs, 2001, 2(1):104-109, Pharma Press Ltd.
Surprisingly, it has now been found that 1-(aminoalkyl)-3-sulfonylindole and -indazole derivatives of formula I demonstrate 5-HT6 affinity. Advantageously, said indole and indazole derivatives may be used as effective therapeutic agents for the treatment of central nervous system (CNS) disorders associated with or affected by the 5-HT6 receptor. Accordingly, the present invention provides 1-(aminoalkyl)-3-sulfonylindole and -indazole derivatives of formula I 
wherein
W is N or CR2;
R is H, halogen, CN, OCO2R7, CO2R8, CONR9R10, SOpR11, NR12R13, OR14, COR15 or a C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, C3-C7cycloalkyl, cycloheteroalkyl, aryl or heteroaryl group each optionally substituted;
R1 is an optionally substituted C1-C6alkyl, C3-C7cycloalkyl, aryl, or heteroaryl group or an optionally substituted 8- to 13-membered bicyclic or tricyclic ring system having a N atom at the bridgehead and optionally containing 1, 2 or 3 additional heteroatoms selected from N, O or S;
R2 is H, halogen, or a C1-C6alkyl, C1-C6alkoxy, C3-C7cycloalkyl, aryl or heteroaryl group each optionally substituted;
R3 and R4 are each independently H or an optionally substituted C1-C6alkyl group;
R5 and R6 are each independently H or a C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, C3-C7cycloalkyl, cycloheteroalkyl, aryl or heteroaryl group each optionally substituted or R5 and R6 may be taken together with the atom to which they are attached to form an optionally substituted 5- to 8-membered ring optionally containing an additional heteroatom selected from O, NR16 or SOx;
m is 0 or an integer of 1, 2 or 3;
n is an integer of 2, 3, 4 or 5;
p and x are each independently 0 or an integer of 1 or 2;
R7, R8, R11, R15 and R16 are each independently H or a C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, C3-C6cycloalkyl, cycloheteroalkyl, aryl or heteroaryl group each optionally substituted;
R9 and R10 are each independently H or a C1-C6alkyl or C3-C7cycloalkyl group each optionally substituted or R9 and R10 may be taken together with the atom to which they are attached to form a 5- to 7-membered ring optionally containing another heteroatom selected from O, NR18 or S;
R12 and R13 are each independently H or an optionally substituted C1-C4alkyl group or R12 and R13 may be taken together with the atom to which they are attached to form a 5- to 7-membered ring optionally containing another heteroatom selected from O, NR17 or SOq;
R14 is a C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, C3-C7cycloalkyl, cycloheteroalkyl, aryl or heteroaryl group each optionally substituted;
q is 0 or an integer of 1 or 2; and
R17 and R18 are each independently H or a C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, C3-C7cycloalkyl, cycloheteroalkyl, aryl or heteroaryl group each optionally substituted; or
a stereoisomer thereof or a pharmaceutically acceptable salt thereof.
As used in the specification and claims, the term halogen designates F, Cl, Br or I and the term cycloheteroalkyl designates a 5- to 7-membered cycloalkyl ring system containing 1 or 2 heteroatoms, which may be the same or different, selected from N, O or S and optionally containing one double bond. Exemplary of the cycloheteroalkyl ring systems included in the term as designated herein are the following rings wherein X is NRxe2x80x2, O or S; and Rxe2x80x2 is H or an optional substituent as described hereinbelow: 
Similarly, as used in the specification and claims, the term heteroaryl designates a 5- to 10-membered aromatic ring system containing 1, 2 or 3 heteroatoms, which may be the same or different, selected from N, O or S. Such heteroaryl ring systems include pyrrolyl, azolyl, oxazolyl, thiazolyl, imidazolyl, furyl, thienyl, quinolinyl, isoquinolinyl, indolinyl, benzothienyl, benzofuranyl, benzisoxazolyl or the like. The term aryl designates a carbocyclic aromatic ring system e.g., having 6 to 14 carbon atoms such as phenyl, naphthyl, anthracenyl or the like. The term haloalkyl as used herein designates a CnH2n+1 group having from one to 2n+1 halogen atoms which may be the same or different and the term haloalkoxy as used herein designates an OCnH2n+1 group having from one to 2n+1 halogen atoms which may be the same or different.
Exemplary of the 8- to 13-membered bicyclic or tricyclic ring systems having a N atom at the bridgehead and optionally containing 1, 2 or 3 additional heteroatoms selected from N, O or S included in the term as designated herein are the following ring systems wherein W2 is NR, O or S; and R is H or an optional substituent as described hereinbelow: 
In the specification and claims, when the terms C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, C3-C7cycloalkyl, cycloheteroalkyl, aryl or heteroaryl as designated as being optionally substituted, the substituent groups which are optionally present may be one or more of those customarily employed in the development of pharmaceutical compounds or the modification of such compounds to influence their structure/activity, persistence, absorption, stability or other beneficial property. Specific examples of such substituents include halogen atoms, nitro, cyano, thiocyanato, cyanato, hydroxyl, alkyl, haloalkyl, alkoxy, haloalkoxy, amino, alkylamino, dialkylamino, formyl, alkoxycarbonyl, carboxyl, alkanoyl, alkylthio, alkylsuphinyl, alkylsulphonyl, carbamoyl, alkylamido, phenyl, phenoxy, benzyl, benzyloxy, heterocyclyl (such as heteroaryl or cycloheteroalkyl) or cycloalkyl groups, preferably halogen atoms or lower (e.g. C1-C6) alkyl groups. Typically, 0-3 substituents may be present. When any of the foregoing substituents represents or contains an alkyl substituent group, this may be linear or branched and may contain up to 12, preferably up to 6, more preferably up to 4 carbon atoms.
Pharmaceutically acceptable salts may be any acid addition salt formed by a compound of formula I and a pharmaceutically acceptable acid such as phosphoric, sulfuric, hydrochloric, hydrobromic, citric, maleic, malonic, mandelic, succinic, fumaric, acetic, lactic, nitric, sulfonic, p-toluene sulfonic, methane sulfonic acid or the like.
Compounds of the invention include esters, carbamates or other conventional prodrug forms, which in general, are functional derivatives of the compounds of the invention and which are readily converted to the inventive active moiety in vivo. Correspondingly, the method of the invention embraces the treatment of the various conditions described hereinabove with a compound of formula I or with a compound which is not specifically disclosed but which, upon administration, converts to a compound of formula I in vivo. Also included are metabolites of the compounds of the present invention defined as active species produced upon introduction of these compounds into a biological system.
Compounds of the invention may exist as one or more stereoisomers. The various stereoisomers include enantiomers, diastereomers, atropisomers and geometric isomers. One skilled in the art will appreciate that one stereoisomer may be more active or may exhibit beneficial effects when enriched relative to the other stereoisomer(s) or when separated from the other stereoisomer(s). Additionally, the skilled artisan knows how to separate, enrich or selectively prepare said stereoisomers. Accordingly, the present invention comprises compounds of Formula I, the stereoisomers thereof and the pharmaceutically acceptable salts thereof. The compounds of the invention may be present as a mixture of stereoisomers, individual stereoisomers, or as an optically active or enantiomerically pure form.
Preferred compounds of the invention are those compounds of formula I wherein n is 2. Also preferred are those compounds of formula I wherein R1 is an optionally substituted phenyl, naphthyl or imidazothiazolyl group. Another group of preferred compounds of formula I are those compounds wherein R3 and R4 are H.
More preferred compounds of the invention are those formula I compounds wherein n is 2 and R2 is H or CH3. Another group of more preferred compounds are those compounds of formula I wherein n is 2 and R5 and R6 are each independently H or C1-C4alkyl. Further more preferred formula I compounds are those compounds wherein n is 2; R is H, halogen or C1-C4alkoxy; R1 is an optionally substituted phenyl, naphthyl or imidazothiazolyl group; and R3 and R4 are H.
Examples of preferred compounds of the invention include:
2-[5-methoxy-3-(phenylsulfonyl)-1H-indol-1-yl]ethylamine;
6-chloro-1-(3-morpholin-4-yl-propyl)-3-(phenylsulfonyl)-1H-indole;
5-methoxy-3-(phenylsulfonyl)-1-(3-pyrrolidin-1-yl-propyl)-1H-indole;
N,N-dimethyl-N-{3-[3-(4-fluorophenylsulfonyl)-5-methoxy-1H-indol-1-yl]-propyl}-amine;
N,N-dibenzyl-N-{[2-(3-phenylsulfonyl)-1H-indol-1-yl]ethyl}amine;
5-methoxy-3-(phenylsulfonyl)-1-(2-pyrrolidin-1-yl-ethyl)-1H-indole;
N,N-dimethyl-N-{2-[3-(4-fluorophenylsulfonyl)-5-methoxy-1H-indol-1-yl]-ethyl}amine;
N,N-dimethyl-3-[3-(phenylsulfonyl)-1H-indol-1-yl]propan-1-amine;
2-[3-(phenylsulfonyl)-1H-indol-1-yl]ethylamine;
2-[3-(naphth-1-ylsulfonyl)-1H-indol-1-yl]ethylamine;
2-{3-[(6-chloro-imidazo[2,1-b][1,3]thiazol-5-yl)lsulfonyl]-1H-indol-1-yl]ethylamine;
3-[3-(phenylsulfonyl)-1H-indol-1-yl]propan-1-amine;
3-[3-(4-fluorophenylsulfonyl)-5-methoxy-1H-indol-1-yl]propan-1-amine;
3-(phenylsulfonyl)-1-(2-piperidin-1-yl-ethyl)-1H-indole;
3-[5-methoxy-3-(phenylsulfonyl)-1H-indol-1-yl]propan-1-amine;
3-[6-chloro-3-(phenylsulfonyl)-1H-indol-1-yl]propan-1-amine;
6-chloro-1-(2-morpholin-4-yl-ethyl)-3-(phenylsulfonyl)-1H-indole;
3-(phenylsulfonyl)-1-(3-piperidin-1-yl-propyl)-1H-indole;
2-[6-chloro-3-(phenylsulfonyl)-1H-indol-1-yl]ethylamine;
2-[3-(4-fluorophenylsulfonyl)-5-methoxy-1H-indol-1-yl]ethylamine;
N,N-dimethyl-N-{2-[2-methyl-3-(phenylsulfonyl)-1H-indol-1-yl]ethyl}amine;
N,N-dimethyl-N-{2-[5-carbonitrile-3-(phenylsulfonyl)-1H-indol-1-yl]ethyl}amine hydrochloride;
N,N-dimethyl-N-{2-[4-fluoro-3-(phenylsulfonyl)-1H-indol-1-yl]ethyl}amine;
N,N-dimethyl-N-{2-[7-chloro-3-(phenylsulfonyl)-1H-indol-1-yl]-ethyl}amine;
N,N-dimethyl-N-{2-[4-chloro-3-(phenylsulfonyl)-1H-indol-1-yl]-ethyl}amine;
N,N-dimethyl-N-{2-[4-methyl-3-(phenylsulfonyl)-1H-indol-1-yl]ethyl}amine;
N,N-dimethyl-N-{2-[7-ethyl-3-(phenylsulfonyl)-1H-indol-1-yl]ethyl}amine;
N,N-dimethyl-{N-[3-(thien-2ylsulfonyl)-1H-indol-1-yl]ethyl}amine;
2-[3-(thien-2-ylsulfonyl)-1H-indol-1-yl]ethylamine;
1-[2-(dimethylamino)ethyl]-3-(phenylsulfonyl)-1H-indole-5-carbonitrile;
1-[2-(dimethylamino)ethyl]-3-(phenylsulfonyl)-1H-indole-7-carbonitrile;
2-[5-methoxy-3-(phenylsulfonyl)-1H-indazol-1-yl)]ethylamine;
6-chloro-1-(3-morpholin-4-yl-propyl)-3-(phenylsulfonyl)-1H-indazole;
5-methoxy-3-(phenylsulfonyl)-1-(3-pyrrolidin-1-yl-propyl)-1H-indazole;
N,N-dimethyl-N-{3-[3-(4-fluorophenylsulfonyl)-5-methoxy-1H-indazol-1-yl]-propyl}-amine;
N,N-dibenzyl-N-{[2-(3-phenylsulfonyl)-1H-indazol-1-yl]ethyl}amine;
5-methoxy-3-(phenylsulfonyl)-1-(2-pyrrolidin-1-yl-ethyl)-1H-indazole;
N,N-dimethyl-N-3-{2-[3-(4-fluorophenylsulfonyl)-5-methoxy-indazol-1-yl]-ethyl}amine;
N,N-dimethyl-N-3-[3-(phenylsulfonyl)-1H-indazol-1-yl]propan-1-amine;
2-[3-(phenylsulfonyl)-1H-indazol-1-yl]ethylamine;
2-[3-(naphth-1-ylsulfonyl)-1H-indazol-1-yl]ethylamine;
2-{3-[(6-chloro-imidazo[2,1-b][1,3]thiazol-5-yl)lsulfonyl]-1H-indazol-1-yl]ethylamine;
3-[3-(phenylsulfonyl)-1H-indazol-1-yl]propan-1-amine;
3-[3-(4-fluorophenylsulfonyl)-5-methoxy-indazol-1-yl]propan-1-amine;
3-(phenylsulfonyl)-1-(2-piperidin-1-yl-ethyl)-1H-indazole;
3-[5-methoxy-3-(phenylsulfonyl)-1H-indazol-1-yl]propan-1-amine;
3-[6-chloro-3-(phenylsulfonyl)-1H-indazol-1-yl]propan-1-amine;
6-chloro-1-(2-morpholin-4-yl-ethyl)-3-(phenylsulfonyl)-1H-indazole;
3-(phenylsulfonyl)-1-(3-piperidin-1-yl-propyl)-1H-indazole;
2-[6-chloro-3-(phenylsulfonyl)-1H-indazol-1-yl]ethylamine;
2-[3-(4-fluorophenylsulfonyl)-5-methoxy-1H-indazol-1-yl]ethylamine;
N,N-dimethyl-N-{2-[2-methyl-3-(phenylsulfonyl)-1H-indazol-1-yl]ethyl}-amine;
N,N-dimethyl-N-{2-[2-methyl-3-(naphth-1-ylsulfonyl)-1H-indazol-1-yl]ethyl}-amine;
N,N-dimethyl-N-{2-[5-carbonitrile-3-(phenylsulfonyl)-1H-indazol-1-yl]ethyl}amine;
N,N-dimethyl-N-{2-[4-fluoro-3-(phenylsulfonyl)-1H-indazol-1-yl]ethyl}amine;
N,N-dimethyl-N-{2-[3-(naphth-1-ylsulfonyl)-1H-indazol-1-yl]ethyl}amine;
N,N-dimethyl-N-{2-{[3-(6-chloro-imidazo[1,2-b][1,3]thiazol-5-yl)sulfonyl]-1H-indazol-1-yl}ethyl}amine;
N,N-dimethyl-N-{2-[7-chloro-3-(phenylsulfonyl)-1H-indazol-1-yl]-ethyl}amine;
N,N-dimethyl-N-{2-[4-chloro-3-(phenylsulfonyl)-1H-indazol-1-yl]-ethyl}amine;
N,N-dimethyl-N-{2-[4-methyl-3-(phenylsulfonyl)-1H-indazol-1-yl]ethyl}-amine;
the stereoisomers thereof; or the pharmaceutically acceptable salts thereof.
Advantageously, the present invention provides a process for the preparation of a compound of formula I which comprises reacting a compound of formula II with a haloalkylamine of formula III in the presence of a base optionally in the presence of a solvent. The process of the invention is shown in flow diagram I wherein Hal represents Cl, Br or I. 
Bases suitable for use in the process of the invention include strong bases such as NaH, KOt-Bu, NaOH or any conventional base capable of removing a proton from a basic indole or indazole nitrogen atom.
Solvents suitable for use in the process of the invention include one or more polar solvents such as dimethyl formamide, dimethylsulfoxide, acetonitrile, tetrahydrofuran, water or the like. If two immiscible solvents are used, a phase transfer catalyst may be present. Preferably, for the preparation of those compounds of formula I wherein R5 and R6 are H, the compound of formula II may be reacted with a base as described hereinabove in the presence of a phase transfer catalyst, such as tetrabutylammonium hydrogensulfate, to give the desired compound of formula I wherein R5 and R6 are H.
Compounds of formula I may also be prepared by reacting the formula II compound with a di-haloalkyl compound of formula IV to give the 1-(haloalkyl)indole or -indazole or formula V and reacting the formula V compound with an amine, HNR5R6, optionally in the presence of a base to give the desired formula I product. The reaction is shown in flow diagram II wherein Hal is Cl, Br or I. 
Compounds of formula II may be prepared using conventional synthetic methods and, if required, standard separation and isolation techniques. For example, for compounds of formula II wherein W is CR2 (IIa), a nitrobenzene compound of formula VI may be reacted with a chloromethylsulfonyl compound of formula VII in the presence of a strong base to give the intermediate of formula VII; said formula VII intermediate may then be treated with a reducing agent such as Fe, Zn or Sn in the presence of an acid to give the amine of formula IX; said amine may then be reacted with the appropriate orthoester of formula X to give the formula XI compound; and said formula XI compound may be cyclized in the presence of a base to give the desired formula IIa 3-sulfonylindole. The general synthetic method is described by W. Wojciechowski and M. Makosza, Synthesis 1986, 651-653. Similarly, the formula IX amine may be reacted with NaNO2 in the presence of an acid to give those indazole compounds of formula II wherein W is N (IIb). The reaction sequences are shown in flow diagram III. 
Compounds of formula II may also be prepared directly from an indole or indazole of formula XII by reacting the formula XII substrate with iodine to give the 3-iodoindole or -indazole of formula XIII; coupling the formula XIII compound with an appropriate thiol of formula XIV to give the 3-thioindole or-indazole of formula XV and oxidizing said formula XV compound with a conventional oxidizing agent such as H2O2, m-chloroperbenzoic acid, or the like to afford the desired formula II intermediate. The reaction is shown in flow diagram IV. 
Alternatively, the formula XV 3-thioindole or -indazole compound may be prepared in a single step from the formula XII substrate by reacting the formula XII compound with the formula XIV thiol in the presence of iodine, preferably in a polar solvent such as aqueous alcohol. The thus-obtained formula XV compounds may then be oxidized as shown hereinabove to give the formula II intermediate. The thus-obtained formula II intermediate may then be carried on to the desired compounds of formula I via the alkylation of the basic indole or indazole nitrogen atom as shown in flow diagrams I and II hereinabove.
Compounds of formula XII may also be converted to the desired compounds of formula I wherein R5 and R6 are other than H (Ia) by reacting the formula XII compound with an amine of formula IIIa wherein R5 and R6 are other than H to give the N-alkylated compound of formula XVI; reacting the formula XVI compound with a sulfonyl chloride of formula XVII, optionally in the presence of a catalyst such as Ag(OSO2CF3) or Bi(OSO2CF3)3, to give the desired compound of formula Ia. Similarly, compounds of formula I wherein R5 and R6 are H (Ib) may be prepared directly from the formula XII intermediate by reacting said formula XII intermediate with a nitrile of formula XVIII to give the corresponding alkylated compound of formula XIX; sulfonylating said formula XIX compound to give the compound of formula XX; and reducing the formula XX compound using conventional reducing reagents such as borane in tetrahydrofuran (THF) to give the desired compounds of formula Ib. The reactions are shown in flow diagram V wherein Hal represents Cl, Br or I. 
Advantageously, the formula I compounds of the invention are useful for the treatment of CNS disorders relating to or affected by the 5-HT6 receptor including motor, mood, personality, behavioral, psychiatric, cognitive, neurodegenerative, or the like disorders, for example Alzheimer""s disease, Parkinson""s disease, attention deficit disorder, anxiety, epilepsy, depression, obsessive compulsive disorder, sleep disorders, neurodegenerative disorders (such as head trauma or stroke), feeding disorders (such as anorexia or bulimia), schizophrenia, memory loss, disorders associated with withdrawal from drug or nicotine abuse, or the like or certain gastrointestinal disorders such as irritable bowel syndrome. Accordingly, the present invention provides a method for the treatment of a disorder of the central nervous system related to or affected by the 5-HT6 receptor in a patient in need thereof which comprises providing said patient a therapeutically effective amount of a compound of formula I as described hereinabove. The compounds may be provided by oral or parenteral administration or in any common manner known to be an effective administration of a therapeutic agent to a patient in need thereof.
The term xe2x80x9cprovidingxe2x80x9d as used herein with respect to providing a compound or substance embraced by the invention, designates either directly administering such a compound or substance, or administering a prodrug, derivative or analog which forms an equivalent amount of the compound or substance within the body.
The therapeutically effective amount provided in the treatment of a specific CNS disorder may vary according to the specific condition(s) being treated, the size, age and response pattern of the patient, the severity of the disorder, the judgment of the attending physician and the like. In general, effective amounts for daily oral administration may be about 0.01 to 1,000 mg/kg, preferably about 0.5 to 500 mg/kg and effective amounts for parenteral administration may be about 0.1 to 100 mg/kg, preferably about 0.5 to 50 mg/kg.
In actual practice, the compounds of the invention are provided by administering the compound or a precursor thereof in a solid or liquid form, either neat or in combination with one or more conventional pharmaceutical carriers or excipients. Accordingly, the present invention provides a pharmaceutical composition which comprises a pharmaceutically acceptable carrier and an effective amount of a compound of formula I as described hereinabove.
Solid carriers suitable for use in the composition of the invention include one or more substances which may also act as flavoring agents, lubricants, solubilizers, suspending agents, fillers, glidants, compression aides, binders, tablet-disintegrating agents or encapsulating materials. In powders, the carrier may be a finely divided solid which is in admixture with a finely divided compound of formula 1. In tablets, the formula I compound may be mixed with a carrier having the necessary compression properties in suitable proportions and compacted in the shape and size desired. Said powders and tablets may contain up to 99% by weight of the formula I compound. Solid carriers suitable for use in the composition of the invention include calcium phosphate, magnesium stearate, talc, sugars, lactose, dextrin, starch, gelatin, cellulose, methyl cellulose, sodium carboxymethyl cellulose, polyvinylpyrrolidine, low melting waxes and ion exchange resins.
Any pharmaceutically acceptable liquid carrier suitable for preparing solutions, suspensions, emulsions, syrups and elixirs may be employed in the composition of the invention. Compounds of formula I may be dissolved or suspended in a pharmaceutically acceptable liquid carrier such as water, an organic solvent, or a pharmaceutically acceptable oil or fat, or a mixture thereof. Said liquid composition may contain other suitable pharmaceutical additives such as solubilizers, emulsifiers, buffers, preservatives, sweeteners, flavoring agents, suspending agents, thickening agents, coloring agents, viscosity regulators, stabilizers, osmo-regulators, or the like. Examples of liquid carriers suitable for oral and parenteral administration include water (particularly containing additives as above, e.g., cellulose derivatives, preferably sodium carboxymethyl cellulose solution), alcohols (including monohydric alcohols and polyhydric alcohols, e.g., glycols) or their derivatives, or oils (e.g., fractionated coconut oil and arachis oil). For parenteral administration the carrier may also be an oily ester such as ethyl oleate or isopropyl myristate.
Compositions of the invention which are sterile solutions or suspensions are suitable for intramuscular, intraperitoneal or subcutaneous injection. Sterile solutions may also be administered intravenously. Inventive compositions suitable for oral administration may be in either liquid or solid composition form.
For a more clear understanding, and in order to illustrate the invention more clearly, specific examples thereof are set forth hereinbelow. The following examples are merely illustrative and are not to be understood as limiting the scope and underlying principles of the invention in any way.
The term HNMR designates proton nuclear magnetic resonance. The terms EtOAc, THF and DMF designate ethyl acetate, tetrahydrofuran and dimethyl formamide, respectively. All chromatography is performed using SiO2 as support.